Temperature-control mechanism.



A. DE KHOTINSKY.

TEMPERATURE CONTROL MECHANISM. APPLICATION FILED JUNE 18, 19M.

1 ,1 84,430. Patent-ed May 23,- 1916.

2 SHEETSSHEET 1.

A. DE KHOTINSKY.

TEMPERATURE CONTROL MECHANISM.

wucmou FILED JUNE 18, 1914.

Patente May 23,1916.

2 SHEETS-SHEET 2- v f J Ola flo n y 7(7)); WW m7;

UNITED STATES PATENT OFFICE.

ACHILLES n1! IGIO'IIDTSKY, OF CHICAGO, ILLINOIS; ASSIGNOR TO CENTRAL SCIENTIFIC COMPANY, or

7 To all whom it may concern:

- siding at Be it known that I, AoHInLEs DE KHocitizen of the United States, re- Chicago, in the county of Cook and State of Illinois,'have invented certain TINSKY, a

new and useful Improvements in Temperature-Control Mechanisms; and I do hereby declare the following to be a full, clean-and exact description of the invention, such as will enable others skilled in the art to which i it appertains to make and use the same.

- in connection My invention relates to electrical mechanisms for controllin temperatures, being particularly suited or use in connection with constant temperature baths and for use with the extremely sensitive thermostat described in my circuit-closing filed June 6, 1914 as copending application ;.$;}:Seria1 Number 843547, in which the current is opened or closed by the expansion or contraction of mercury within a tube of very small bore. In using such sensitive ther- I mostats, the difficulties due to' sparking at the mercury contact are greatly increased, as a small amount of the oxid of mercury produced by the spark will clog the bore and interfere with the sensitive operationof the device. -Even if the thermostat is operatedg'by batteries, the self-induction in the magretic switches or relays commonly used in connection with such thermostats will cause too great an amount -of sparking to make such apparatus dependable in opera tion. Besides, the use of batteries involves a'steady watching of their voltage, as the accuracy in maintainingthe temperature of a bath constant to within minute fractions of a degree requires a much more frequent operation of the mechanism than .is demanded by a less sensitive temperature control; consequently, the batteries will deteriorate rapidly and if unexpectedly exhausted, 7

they may easily put theapparatus out of commission and spoil the results for which the bath was intended.

' One object of my invention is to provide a control mechanism which will permit of such an extremely sensitive operation without, causing injurious sparking within the Specification of Letters Patent.

bracket or strip CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TEMPERATURE-CONTROL MECHANISM.

out damaging the contacts at which either the heating or the regulating currents are made and broken.

Another object is to provide a mechanism which will automatically compensate for variations in temperature both within the liquid of the bath and in the air of the room surrounding the bath.

Still another object is to provide means for insurlng a good magnetic connection between the pivoted armatures of the actuatlng magnets and the adjacent fixed portions of the magnetic circuit regardless of the position in which the said magnets ma;

be mounted. v

I. accomplish these objects by the c0nstruction shown in the accompanying drawing, in which:

Figure -1- is a plan view, partly in section and partly diagrammatic,'of. an. electrical control mechanism embodying a part of my invention. Fig. 2 is a fragmentary side elevation of the. same. Fig. -3- is a transverse section through Fig. -1 along the line 3-3. Fig. 4 is a sectional view of a constant temperature bath and a partially diagrammatic view of the control mechanism of myinvention as connected, thereto. Fig. 5 is an enlarged detail view of the armature-of one of the magnets and a portion of the adjacent magnet frame.

In the embodiment of Fig. -4-, my invention is shown as used in connection with the terminal wires 1 and 2 of an ordinary lighting circuit, one of which wires is permanently connected to one terminal of each of a plurality of heating elements Sand 4 immersed in the liquid of a bath '6, the said elements being supported by a suita 7. The strip 7 also supports a thermostat 13 having its main portion immersed in the liquid 5 'of the bath and a Patented May 23, 1916.

Application filed June 18, 1914. Serial No. 845,813.

ble

thermostat 14 exposed to the air of theroom but not immersed in the said liquid; The

thermostats used may be of any suitable type, but are here pictured in the form corresponding to mycopending application. The other terminals of the heating elements, which elements are arranged in two distinct groups 3 and 4, I connect respectively to independent contact tips 21, the tips connected to the heating elements of each group being insulated from each other but disposed in proximity to each other with the extreme tip portions'preferabl'y disposed in substantially the same plane. Positioned near the said tips of the said contact terminals and connected respectively to the two groups of heating elements are movable contact members 16 and 17 both of which contact members are permanently connected by a wire 15 to the current-supply wire 2. The movable contact members 16 and 17 are preferably equipped with multi-forked ends 20 providing independent forks adapted to contact respectively with the said free terminals 21 of the heating elements, so that when each of the saidmovable contact members is in the position of Fig. 4-,-it will simultaneously close the circuit through all of the corresponding heating elements, which will thus be connected in multiple to the current-supply circuit.

To manipulate the movable contact members 16 and 17 I associate therewith the armatures 18 and 19 of magnets 11 and 12 controlled respectively by the said thermostats 13 and 14. The winding of each of these electro-magnets is connected in series with the corresponding thermostat and with a suitable low voltage supply of current, for which purpose I preferably utilize a low voltage and low-amperage current derived from the sup 1y circuit as shown in Fig.4. To obtain t e same, I bridge a pair of resistances 8 and 9 in series across the supply wires 1 and 2, the said resistances being so high as to permit the voltage of the circuit to force only a quite small volume of current through the same. I then include each of the said magnets and the corresponding thermostatin series in a circuit shunting a small portion of the resistance member formed by the joint resistance of the elements 8 and 9, so that each of the said magnets will be subject to only a small fraction of the voltage of the supply circuitand to only a portion of the volume of current flowing through the said resistances. The extreme tip portions of the contact ti s 21 (which portions are made of platmum, tungsten or other relatively non-sparking metal) are preferably mounted upon finely threaded screws 27 threaded into metal bushings 28, which bushings in turn are carried by vertical posts 29 of slate or other suitable insulating material. I then 'con nect the other end of the adjusting screws 27 to suitable conducting strips 30 (as shown in Fig. 1), through which the circuit is continued as shown diagrammatically in Fig.

In operation, Fig.4 shows both magnets as closing the circuit through .the heating elements, so as to su ply an increase of term perature to the liquid in the bath. As soon as the liquid reaches the temperature for which the thermostat 13 is adjusted, the

circuit will be closed by the saidthermostat through the, magnet 11, thereby causmgfthe one of the said latter to attract its armature 18 and open the circuit through the heaters 3, after which the said circuits will be kept open by the attraction of the magnet 11 for its armature until the temperature in the bath decreases and opens the circuit in the thermostat 13. When this occurs, the magnet 11 releascsits armature 18, thereby allowing the bifurcated contact 16 to close the circuit again through the heating elements 3. Likewise, the companion thermostat 14 will cause the magnet 12 to be actuated in response to variations in the temperature of the surrounding air thereby controlling the companion heater elements 4. Instead of pivoting each of the said armatures 18 and 19 upon rock shafts, I preferably equip them at one end with knife-edge formations 22 adapted to tal position, as shown in Fig. *-5, the

knife-edge is easily maintained inoperative position by gravity, unless'the mechanism is severely jarred. However, if the magnet is jarred or if the apparatus is so disposed that the bar 24 will occupy a vertical mstead of a horizontal position the armature may slide with respect to the notch in the adjacent bar and in the case of an apparatus like mine, the contact membefs 16 may then support the said armature floatingly upon the terminals 21 independent of the said notch 23, thereby interrulpting the magnetic circuit. To avoid this, ture with a recess 25 housing a spiral spring 26 connected at one end to the said armature and at its other end to the bar 24 and continuously by drawing the said knife-edge formation into the said slot so as to mainequip each arma the said parts. By connecting one terminal of each of the heating elements constituting by finely threa edscrews, I am able to adjust these tips with respect to each other and to the adjacent forks of the movable contact member so that the contact through the respective forks of the said member will be made or broken successively of each other.

In practice, I- have found that owing to th'e'difierence in the ionization of the air at'the respective contacts, the contacting of the respective tip and fork .portions will not be simultaneous even if the adjustment would visually imply that the action should be simultaneous. Consequently, by thusequipping the movable contact member with independent forks, I am able to provide a successive. opening or closing ofthe respec- 130' oups to contact tips carried tive circuits through the heating elements of a groupwhile only providing a very slight movement of the. movable member and the armature associated threwith. By thus restricting the said movement of the armature, I reduce the self-induction in the magnet and thereby avoid the injurious sparking which as heretofore been encountered within I the thermostat tubes when operated with other control mechanisms. Moreover, by sub-dividing the heating means into a number of elements connected in multiple and each consuming relatively small amounts of current, I greatly decrease the danger of burning the contacts between the members 16 and 21 and the members 17 and 21, upon the opening or closing of the circuit.

Where the bath in which the temperature is to be controlled is relatively large, the number of heating elements comprised by each of the two groups and the corresponding division of the current through the same may be increased by increasing the number of contact forks'upon the movable currentcarrying member actuated by the armature of each magnet. Moreover, it will be obvious that the various details herein disclosed might be modified in many other .ways

without departing from the spirit of my invention. For example, if the available voltage is comparatively low, the resistance member may be omitted and connections made by wires 31, as shown in Fig. 4:.

I claim as my invention:

1. Heating apparatus, comprising in combination with a pair of current supply wires; a plurality of electric heating elements having one terminal of each permanently connected to one of the said wires, the

other terminals thereof connected respectively toindependent contact tips; a movable contact member equipped with a plurality of contact portions adapted respectively and successively to contact with the said contact tips; a thermostatic circuit closer; an electro-magnet operatively connected to the said contact member; and a source of current connected in series with said thermostat and the winding of said electro-magnet. p

2. Heating apparatus, comprising in combination with a pair of current supply wires and a bath, a plurality of electric heating elements disposed in said bath, one terminal of each of said heating elements permanently connected to one of the said wires, the said heating elements arranged in two groups; the other terminals of the heating elements connected respectivelyto independent contact tips, the contact tipsconnected to each group of heating elements being disposed in proximity to each other; a pair of independently movable contact members permanently connected to the other of the said wires and presenting contact portions adapted successively to impinge respectively against the contact tips of the respective groups; a resistance member bridged across the said wires; a pair of circuit closing thermostats subject respectively to the temperature of the bath and the temperature outside of the said bath, one terminal of each being jointly connected to one of the said wires; and a pair of electro-magnets operatively connected respectively to the said movable contact members, the windings of each magnet connected respectively in series with-one of said thermostats in a circuit shunting a portion of the said resistance.

3. Heating apparatus, comprising in combination with current supply wires and a bath, a plurality of electric heating elements terminals of the said heating elements; a

tro-magnet operatively connected to the said windings of said magnet connected respectively to the other t erminal of the said thermostatic circuit-closer and to the said resistance intermediate of the ends of the latter, whereby the said winding and the terminals of the said thermostatic circuitcloser are in a circuit shunting a portion of the said resistance. r

4. Heating apparatus, comprising in combination with a pair of current supply wires, a resistance bridged across the said wires; a plurality of electric heating elements having one terminal of each permanently connected to one of the said wires, the other terminals thereof connected re spectively to independent contact tips; a movable contact member equipped with a movable contact member, the ends of the plurality of contact portions adapted respectively and successively to contact with the said contact tips; a thermostatic circuit closer; and an electro-magnet operatively being independently adjustable;

magnet.

6; Heating apparatus, comprising in combination with a pair of current supply wires and a bath, a plurality of electric heating elements disposed in said bath, one terminal of each of said heating elements permanently connected to one of the said Wires, the said heating elements arranged in two groups; the other terminals of the heating elements connected respectively to independent contact tips, the contact tips connected to each group of heating elements means subject respectively to the temperature of the bath and of the surrounding air; and connections between the other of said Wires and each group of contact tips, the connections for each of said groups controlled respectively by one of the said control means.

, 7. Heating apparatus, comprising in combination'with a pair of current supply Wires and a bath, a plurality of electric heating elements disposed in said bath, one terminal of each of said heating elements permanently connected to one of the said wires, the said heating elements arranged in two groups; the 'other terminals of the heating elements connected respectively to independent contact tips, the contact tips connected to each group of heating elements control,

being independently adjustable; control means subject respectively to the temperature of the bath and of the surrounding air; and connections between. the other of said wires and each'group of contact tips, the connections for each of said groups controlled respectively by one of said control of each of said heating elements permanently connected to one of the said wires, the said heating elements arranged in two groups; the other terminals of the heating elements connected respectively to independent contact tips, the contact tips connected to each group of heating elements being independently adjustable; a resistance bridged across the said wires; a pair of thermostats subject respectively to the temperature of the bath and of the surrounding air; an electromagnet in series with each of said thermostats in a circuit shunting a portion of said resistance; and a pair of movable contacts controlled respectively by the said electromagnets and connected to the other of the said Wires, said contacts respectively contacting with the one of said groups of tips.

- In testimony whereof I have signed my ,name in presence of two subscribing witnesses.

ACHILLES DE KHOTINSKY. Witnesses:

ALBERT SCHEIBLE,

M. M. Borne. 

